Osteonecrosis of the jaw in patients transitioning from bisphosphonates to denosumab treatment for osteoporosis.

Antiresorptive-related osteonecrosis of the jaw (ARONJ) is a rare but severe side effect of antiresorptive treatment with bisphosphonates or RANKL-antibody denosumab in patients with malignant diseases or osteoporosis. Whilst osteonecrosis of the jaw (ONJ) related to the administration of bisphosphonates (BPs) has been investigated for more than 1 decade now, only few data are available on denosumab-related ONJ, especially in patients with osteoporosis. From 2008 to 2016, 52 osteoporosis patients were treated with ARONJ in the Department of Oral and Maxillofacial Surgery, University Medical Center Freiburg, Germany. In all patients, a surgical regimen consisting of complete removal of necrotic bone, primary wound closure and perioperative i.v. antibiotic therapy was applied. Of the 52 patients, 38 developed ARONJ after BP monotherapy; in 11 patients, antiresorptive therapy had been transitioned from BPs to denosumab and 3 patients had received denosumab monotherapy. From July 2013, when the first patient with ONJ and transitioning therapy from BPs to denosumab presented to our department, to October 2016, we found recurrences in 17.6% of the patients with BP monotherapy and in 45.5% of the patients with transitioning therapy from BPs to denosumab. Transitioning antiresorptive therapy from BPs to denosumab may be an additional risk factor for developing ARONJ. In these patients, treatment of ARONJ-lesions seems to provoke more complications. An additional dental screening before transitioning should be initiated. Further studies are needed to evaluate if a first-line treatment with denosumab decreases the incidence of ARONJ in patients with osteoporosis and simplifies its treatment.

Review of free software tools for image analysis of fluorescence cell micrographs.

An increasing number of free software tools have been made available for the evaluation of fluorescence cell micrographs. The main users are biologists and related life scientists with no or little knowledge of image processing. In this review, we give an overview of available tools and guidelines about which tools the users should use to segment fluorescence micrographs. We selected 15 free tools and divided them into stand-alone, Matlab-based, ImageJ-based, free demo versions of commercial tools and data sharing tools. The review consists of two parts: First, we developed a criteria catalogue and rated the tools regarding structural requirements, functionality (flexibility, segmentation and image processing filters) and usability (documentation, data management, usability and visualization). Second, we performed an image processing case study with four representative fluorescence micrograph segmentation tasks with figure-ground and cell separation. The tools display a wide range of functionality and usability. In the image processing case study, we were able to perform figure-ground separation in all micrographs using mainly thresholding. Cell separation was not possible with most of the tools, because cell separation methods are provided only by a subset of the tools and are difficult to parametrize and to use. Most important is that the usability matches the functionality of a tool. To be usable, specialized tools with less functionality need to fulfill less usability criteria, whereas multipurpose tools need a well-structured menu and intuitive graphical user interface.

Automatic texture-based analysis in ultrasound imaging of ovarian masses.

PURPOSE: To assess the diagnostic accuracy of a new automatic texture-based algorithm (ATBA) in ultrasound imaging of ovarian masses and to compare its performance to subjective assessment by examiners with different levels of ultrasound experience. MATERIALS AND METHODS: A total of 105 ultrasound images from three different groups of ovarian lesions (malignancies, functional cysts, and dermoid cysts) were evaluated using ATBA and by a total of 36 examiners with four different levels of experience (9 junior trainees, 8 senior trainees, 11 senior gynecologists, and 8 experts). Cohen's κ, Youden's indices, and the sensitivity and specificity of ATBA and of each observer were calculated for every subgroup of ovarian lesions. RESULTS: ATBA classified 78 of the 105 masses correctly (κ = 0.62) - results that were significantly better than those of the junior and senior trainees (p = 0.02 and p < 0.01), while differences from the group of level II examiners did not reach statistical significance (p = 0.27). The best diagnostic performance (κ = 0.70) was obtained by the group of expert level III ultrasonographers. The best classification rates overall, including both ATBA and subjective assessments, were achieved in the detection of functional cysts (Youden's indices from 0.73 to 0.85), while the poorest diagnostic performance was obtained for the classification of dermoid cysts (Youden's indices from 0.28 to 0.55). CONCLUSION: ATBA showed a significantly better diagnostic performance than observers with low or medium levels of experience, emphasizing its potential value for training purposes and in providing additional diagnostic assistance for inexperienced observers.

Computer-assisted diagnosis for precancerous lesions in the esophagus.

OBJECTIVES: The interpretation of endoscopic findings by gastroenterologists is still a difficult and highly subjective task. Despite important developments such as chromo-endoscopy, pit pattern analysis, fluorescence imaging as well as narrow band imaging it still requires lots of experience and training with a certain tentativeness until the final biopsy. By the development of computer-assisted diagnosis (CAD) systems this process can be supported. METHODS: This paper presents a new approach to CAD for precancerous lesions in the esophagus based on color-texture analysis in a content-based image retrieval (CBIR) framework. The novelty of our approach lies in the combination of newly developed color-texture features with the interactive feedback loop provided by a relevance feedback algorithm. This allows the expert to steer the query and is still robust against accidental false decisions. RESULTS: We reached an inter-rater reliability of kappa = 0.71 on a database of 390 endoscopic images. The retrieval accuracy didn't change significantly until a wrong decision rate of 20%. CONCLUSIONS: Thus, the system could be able to support practitioners with less experience or in private practice. In combination with a connected case database it can also support case-based reasoning for the diagnostic decision process.

A semantic approach to segmentation of overlapping objects.

OBJECTIVES: This paper aims at introducing a novel approach for segmentation of overlapping objects and at demonstrating its applicability to medical images. METHODS: This work details a novel approach enhancing the known theory of full-segmentation of an image into regions by lifting it to a semantic segmentation into objects. Our theory allows the formal description of partitioning an image into regions on the first level and allowing the occurrence of overlaps and occlusions of objects on a second, semantic level. Possible applications for the use of this 'semantical segmentation' are the analysis of radiographs and micrographs. We demonstrate our approach by the example of segmentation and separation of overlapping cervical cells and cell clusters on a set of 787 image pairs of registered PAP- and DAPI-stained micrographs. The semantical cell segmentation yielding areas of cell plasmas and nuclei are compared to a manual segmentation of the same images, where 2212 cells have been labeled. A direct comparison of over and under-segmentation between the two segmentation sets yields a mean difference value of 10.15% for the nuclei and 10.80% for the plasma. RESULTS: Using the proposed theory of semantical segmentation of images in combination with adequate models of the image contents, our approach allows identifying, separating and distinguishing several overlapping, occluding objects in medical images. Applying the proposed theory to the application of cervical cell segmentation from overlapping cell clusters and aggregates, it can be seen that it is possible to formally describe the complex image contents. CONCLUSIONS: The proposed method of semantical segmentation is a mighty tool and under the assumption of the subtractive transparency model can be used in different medical image processing applications such as radiology and microscopy. By using alternative models to solve the ambiguities attached to overlaps and occlusions, further fields of application can be addressed.

Design and preliminary evaluation of an extraoral Gow-Gates guiding device.

Incidence of unsuccessful anesthesia with the Gow-Gates mandibular block may be greater than that for the inferior alveolar nerve block until the administrator gains experience with this technique. The aim of this study was to develop a support instrument for the Gow-Gates mandibular block in an attempt to make the described procedure easier and more precise, especially for beginners. In a preliminary clinical experiment 40 patients were anesthetized with this new device; a control group of 40 patients was anesthetized without the instrument. The operators were 80 dental students without previous clinical experience in the Gow-Gates technique. In the experimental group 39 (97.5%) of the 40 patients were provided with complete anesthesia. In the control group 31 (77.5%) of the 40 patients were completely anesthetized. It appears that the new device allows a great level of success with the Gow-Gates mandibular block, irrespective of the clinical experience of the operator.

[Experiences with 'optical' biopsies of leukoplakia of the vocal folds]. / Erfahrungen mit optischen Stimmlippenbiopsien bei Leukoplakien.

BACKGROUND: It is often difficult to distinguish leucoplakia from carcinoma or chronic laryngitis. In this study, we examined if color texture optical biopsies are able to detect leukoplakia reliably and to distinguish this from normal vocal fold tissue. METHODS: 25 images from patients with a normal larynx and 25 images from patients with leucoplakia were analysed retrospectively. The images were recorded with a rigid 90 degrees -laryngoscope (Wolf Typ 4450.571) during a clinical setting and were recorded by a S-VHS-videorecorder. With a software program (InSegT), regions with leucoplakia, normal tissue and suspicious tissue were manually marked. Within each marked region, the use of color texture analysis numeric features were calculated to characterize the surface in texture and color. Color histogramms (HST), Sum- and Difference histogramms (S/D), Statistical Geometric Features (SGF) and Grey-Value-Dependent-Matrix (GLDM) were used. PATIENTS: 29 women and 21 men (age 18 to 81 years, average of 53 years), who were examined in our clinic from 10/1999 - 8/2003, took part in this study. RESULTS: The automatized classification for color texture analysis resulted in 71 % for leucoplakia and 97 % for normal tissue. CONCLUSION: Optical biopsies can contribute to find the correct diagnosis. However, classification results must still get better when optical biopsies should be used in clinical practice.